The shield user skill could also affect the amount of damage that the shield actually takes, since a more skilled user can take blows at more oblique angles.
Yes, but that's somewhat iffy. Deflecting attacks away from you is always good, but that's what armor is for--most pieces of plate armor have convex curves, so blows will slide right off. Shields, in contrast, were frequently given con
cave fronts, so that attacks hitting the shield would tend to STAY on the shield, and not glance away & hit something more vulnerable. But yes, a more experienced shield user would know how to deflect safely.
Historically, most blades were blocked with the edge of a shield instead of the face.
If by "blades" you mean
swords, that's because most swords aren't heavy enough to go through a shield--so their users weren't
trying to, they were trying to stab/cut
next to the shield, at vital targets that weren't quite covered. But, if "blades" is expanded to include
axes, then that's quite wrong: Axes were used to break wooden shields (and in some cases, the arms holding them) all the time. Unless the shield was made of 2-ply wood with the grains running at right angles to each other, a good axeman could break a shield in 1 blow.
To my knowledge shields only get worn when you attack with them which is not a very smart thing to do in most cases. Regardless of this, squads use their shields offensively and I could imagine soldiers in fort mode dying because their shields broke, but this does not affect adventurers as players are too smart to break their shields on purpose.
1. Shields take damage all the time, more often than all other pieces of armor. Any decent warrior knows it's a lot faster & cheaper to replace a shield than, say, a breastplate, and so would block with his shield as much as possible.
2. Attacking with your shield IS surprisingly often a very good thing to do. Shieldbash, pin your opponent's weapon arm against a wall, get it in his face & obscure his vision, jab the upper edge into his throat/jaw, etc.